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Daniela Ekendahl, Peter Rubovic, Pavel Žlebcík, Ondrej Huml, Helena Malá
Salt (NaCl) represents a radiation sensitive material with a considerable potential for dosimetry in mixed radiation fields of photons and neutrons. In consequence of a gamma radiation exposure, it exhibits a strong luminescence signal following stimulation with blue light. Optically stimulated luminescence (OSL) technique can be used for measurement. Photon dose reconstruction can be done using so-called Single-Aliquot Regenerative-dose protocol. However, a part of OSL signal is caused by NaCl self-irradiation resulting from neutron reactions...
August 22, 2017: Radiation Protection Dosimetry
Irina I Ivanova, Yury G Kolyagin, Ivan A Kasyanov, Alexander V Yakimov, Tatiana O Bok, Dmitry N Zarubin
Time-resolved 13C, 23Na, 27Al and 29Si MAS NMR has been applied in situ for monitoring the hydrothermal synthesis of zeolite BEA. Isotopic labelling with 29Si and 13C isotopes has been used to follow the fate of silicious species and structure directing agent ((13CH3-CH2)4NOH). Two mechanistic pathways, namely, solution mediated and solid-solid hydrogel rearrangement have been distinguished for two synthesis procedures studied. The mechanisms of structure directing behavior of TEA+ cations in two reaction pathways have been elucidated...
September 20, 2017: Angewandte Chemie
Régis Guégan, Emmanuel Veron, Lydie Le Forestier, Makoto Ogawa, Sylvian Cadars
The aggregation of surfactants on solid surfaces as they are adsorbed from solution is the basis of numerous technological applications such as colloidal stabilization, ore flotation, and floor cleaning. The understanding of both the structure and the dynamics of surfactant aggregates applies to the development of alternative ways of preparing hybrid layered materials. For this purpose, we study the adsorption of the triethylene glycol mono n-decyl ether (C10E3) nonionic surfactant onto a synthetic montmorillonite (Mt), an aluminosilicate clay mineral for organoclay preparation with important applications in materials sciences, catalysis, wastewater treatment, or as drug delivery...
September 12, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
Krista A Shisler, Rachel U Hutcheson, Masaki Horitani, Kaitlin S Duschene, Adam V Crain, Amanda S Byer, Eric M Shepard, Ashley Rasmussen, Jian Yang, William E Broderick, Jessica L Vey, Catherine L Drennan, Brian M Hoffman, Joan B Broderick
Pyruvate formate-lyase activating enzyme (PFL-AE) is a radical S-adenosyl-l-methionine (SAM) enzyme that installs a catalytically essential glycyl radical on pyruvate formate-lyase. We show that PFL-AE binds a catalytically essential monovalent cation at its active site, yet another parallel with B12 enzymes, and we characterize this cation site by a combination of structural, biochemical, and spectroscopic approaches. Refinement of the PFL-AE crystal structure reveals Na(+) as the most likely ion present in the solved structures, and pulsed electron nuclear double resonance (ENDOR) demonstrates that the same cation site is occupied by (23)Na in the solution state of the as-isolated enzyme...
August 30, 2017: Journal of the American Chemical Society
Markus Krengel, Anna-Lena Hansen, Maximilian Kaus, Sylvio Indris, Niklas Wolff, Lorenz Kienle, David Westfal, Wolfgang Bensch
The ternary compound CuV2S4 exhibits an excellent performance as anode material for sodium ion batteries with a high reversible capacity of 580 mAh g(-1) at 0.7 A g(-1) after 300 cycles. A Coulombic efficiency of ≈99% is achieved after the third cycle. Increase of the C-rate leads to a drop of the capacity, but a full recovery is observed after switching back to the initial C-rate. In the early stages of Na uptake first Cu(+) is reduced and expelled from the electrode as nanocrystalline metallic Cu. An increase of the Na content leads to a full conversion of the material with nanocrystalline Cu particles and elemental V embedded in a Na2S matrix...
June 16, 2017: ACS Applied Materials & Interfaces
Sohei Sukenaga, Pierre Florian, Koji Kanehashi, Hiroyuki Shibata, Noritaka Saito, Kunihiko Nakashima, Dominique Massiot
The description of the structure of aluminosilicate glasses is more often centered on its cationic constituents, and oxygen ions determine their connectivity, directly impacting the physical properties of those disordered materials. A very powerful approach to ascertain this short- to medium-range order is to use (17)O NMR, but up to now the speciation of the chemical bonds was only ambiguously achieved for multicomponent glasses. Here, we propose to directly probe the very scarcely explored through-bond correlations using (17)O{(27)Al} and (17)O{(23)Na} solid-state nuclear magnetic resonance (NMR) double-resonance experiments...
May 8, 2017: Journal of Physical Chemistry Letters
Joshua M Stratford, Martin Mayo, Phoebe K Allan, Oliver Pecher, Olaf J Borkiewicz, Kamila M Wiaderek, Karena W Chapman, Chris J Pickard, Andrew J Morris, Clare P Grey
The alloying mechanism of high-capacity tin anodes for sodium-ion batteries is investigated using a combined theoretical and experimental approach. Ab initio random structure searching (AIRSS) and high-throughput screening using a species-swap method provide insights into a range of possible sodium-tin structures. These structures are linked to experiments using both average and local structure probes in the form of operando pair distribution function analysis, X-ray diffraction, and (23)Na solid-state nuclear magnetic resonance (ssNMR), along with ex situ (119)Sn ssNMR...
May 16, 2017: Journal of the American Chemical Society
Christoph Kopp, Christian Beyer, Peter Linz, Anke Dahlmann, Matthias Hammon, Jonathan Jantsch, Patrick Neubert, Daniela Rosenhauer, Dominik N Müller, Alexander Cavallaro, Kai-Uwe Eckardt, Georg Schett, Friedrich C Luft, Michael Uder, Jörg H W Distler, Jens Titze
No abstract text is available yet for this article.
April 1, 2017: Rheumatology
Neal K Bangerter, Grayson J Tarbox, Meredith D Taylor, Joshua D Kaggie
Sodium magnetic resonance imaging (MRI), or imaging of the 23Na nucleus, has been under exploration for several decades, and holds promise for potentially revealing additional biochemical information about the health of tissues that cannot currently be obtained from conventional hydrogen (or proton) MRI. This additional information could serve as an important complement to conventional MRI for many applications. However, despite these exciting possibilities, sodium MRI is not yet used routinely in clinical practice, and will likely remain strictly in the domain of exploratory research for the coming decade...
December 2016: Quantitative Imaging in Medicine and Surgery
Christoph Kopp, Christian Beyer, Peter Linz, Anke Dahlmann, Matthias Hammon, Jonathan Jantsch, Patrick Neubert, Daniela Rosenhauer, Dominik N Müller, Alexander Cavallaro, Kai-Uwe Eckardt, Georg Schett, Friedrich C Luft, Michael Uder, Jörg H W Distler, Jens Titze
Objective.: Skin fibrosis is the predominant feature of SSc and arises from excessive extracellular matrix deposition. Glycosaminoglycans are macromolecules of the extracellular matrix, which facilitate Na + accumulation in the skin. We used 23 Na-MRI to quantify Na + in skin. We hypothesized that skin Na + might accumulate in SSc and might be a biomarker for skin fibrosis. Methods.: In this observational case-control study, skin Na + was determined by 23 Na-MRI using a Na + volume coil in 12 patients with diffuse cutaneous SSc and in 21 control subjects...
April 1, 2017: Rheumatology
Zoë E M Reeve, Christopher J Franko, Kristopher J Harris, Hossein Yadegari, Xueliang Sun, Gillian R Goward
(23)Na MAS NMR spectra of sodium-oxygen (Na-O2) cathodes reveals a combination of degradation species: newly observed sodium fluoride (NaF) and the expected sodium carbonate (Na2CO3), as well as the desired reaction product sodium peroxide (Na2O2). The initial reaction product, sodium superoxide (NaO2), is not present in a measurable quantity in the (23)Na NMR spectra of the cycled electrodes. The reactivity of solid NaO2 is probed further, and NaF is found to be formed through a reaction between the electrochemically generated NaO2 and the electrode binder, polyvinylidene fluoride (PVDF)...
January 18, 2017: Journal of the American Chemical Society
James C Pramudita, Aditya Rawal, Mohammad Choucair, Daniele Pontiroli, Giacomo Magnani, Mattia Gaboardi, Mauro Riccò, Neeraj Sharma
Two chemically synthesized defective graphene materials with distinctly contrasting extended structures and surface chemistry are used to prepare sodium-ion battery electrodes. The difference in electrode performance between the chemically prepared graphene materials is qualified based on correlations with intrinsic structural and chemical dissimilarities. The overall effects of the materials' physical and chemical discrepancies are quantified by measuring the electrode capacities after repeated charge/discharge cycles...
December 28, 2016: ACS Applied Materials & Interfaces
Donato Belmonte, Carlo Gatti, Giulio Ottonello, Pascal Richet, Marino Vetuschi Zuccolini
Thermodynamic and thermophysical properties of Na2SiO3 in the Cmc21 structural state are computed ab initio using the hybrid B3LYP density functional method. The static properties at the athermal limit are first evaluated through a symmetry-preserving relaxation procedure. The thermodynamic properties that depend on vibrational frequencies, viz., heat capacities, thermal expansion, thermal derivative of the bulk modulus, thermal correction to internal energy, enthalpy, and Gibbs free energy, are then computed in the framework of quasi-harmonic approximation...
November 10, 2016: Journal of Physical Chemistry. A
Johannes Budjan, Urs Benck, Alexander Lammert, Melissa M Ong, Miryana Mircheva, Steffen Diehl, Simon Konstandin, Lothar R Schad, Bernhard K Krämer, Stefan O Schoenberg, Stefan Haneder
BACKGROUND/AIM: Renal denervation (RDN) has been considered a promising therapy option for patients suffering from therapy-resistant hypertension. Besides, in blood-pressure regularization, the kidneys play a fundamental role in sodium ((23)Na) homeostasis. This study assesses the effect of RDN on renal (23)Na concentration using (23)Na magnetic resonance imaging (MRI). PATIENTS AND METHODS: Two patients with therapy-resistant hypertension underwent RDN. (23)Na-MRI, (1)H-MRI, including diffusion weighted imaging (DWI), as well as endothelial dysfunction assessment, were performed 1 day prior, as well as 1, 30 and 90 days after RDN...
September 2016: In Vivo
Eva Sperling, Kamil Górecki, Torbjörn Drakenberg, Cecilia Hägerhäll
It has long been known that the three largest subunits in the membrane domain (NuoL, NuoM and NuoN) of complex I are homologous to each other, as well as to two subunits (MrpA and MrpD) from a Na+/H+ antiporter, Mrp. MrpA and NuoL are more similar to each other and the same is true for MrpD and NuoN. This suggests a functional differentiation which was proven experimentally in a deletion strain model system, where NuoL could restore the loss of MrpA, but not that of MrpD and vice versa. The simplest explanation for these observations was that the MrpA and MrpD proteins are not antiporters, but rather single subunit ion channels that together form an antiporter...
2016: PloS One
Ying Yan, Chuanbao Zhang, Jiangtao Zhang, Tianjiao Zhang, Weiyan Zhou, Jie Zeng, Wenxiang Chen
BACKGROUND: Serum sodium and magnesium are important clinical laboratory tests and accurate testing results are needed for the correct interpretation of the tests. Standardization of serum sodium and magnesium measurements requires simple and reliable reference methods. METHODS: Inductively coupled plasma mass spectrometry (ICP-MS) methods for the measurement of serum sodium and magnesium were developed. Aluminum was used as an internal standard. Serum samples were spiked with the internal standard, digested with 69% nitric acid at 150 degrees C and measured for 23Na/27Al and 24Mg/27Al ratios by ICP-MS...
2016: Clinical Laboratory
Jiri Brus, Libor Kobera, Martina Urbanova, Barbora Doušová, Miloslav Lhotka, David Koloušek, Jiří Kotek, Pavel Čuba, Jiri Czernek, Jiří Dědeček
Nanostructured materials typically offer enhanced physicochemical properties because of their large interfacial area. In this contribution, we present a comprehensive structural characterization of aluminosilicate hybrids with polymer-conjugated nanosized zeolites specifically grown at the organic-inorganic interface. The inorganic amorphous Al-O-Si framework is formed by alkali-activated low-temperature transformation of metakaoline, whereas simultaneous copolymerization of organic comonomers creates a secondary epoxide network covalently bound to the aluminosilicate matrix...
March 22, 2016: Langmuir: the ACS Journal of Surfaces and Colloids
A V Uskov, D Yu Nefedov, E V Charnaya, J Haase, D Michel, Yu A Kumzerov, A V Fokin, A S Bugaev
(23)Na NMR studies of sodium nanoparticles confined to porous glass with the 3.5 nm mean pore size were carried out. The emergence of the second component of the NMR line was observed below 240 K that evidences the occurrence of another modification of metallic sodium. The phase transition temperature is much higher than the martensite transformation temperature in bulk sodium.
January 13, 2016: Nano Letters
Philipp Eisele, Simon Konstandin, Martin Griebe, Kristina Szabo, Marc E Wolf, Angelika Alonso, Anne Ebert, Julia Serwane, Christina Rossmanith, Michael G Hennerici, Lothar R Schad, Achim Gass
BACKGROUND: Advanced magnetic resonance imaging (MRI) techniques provide a window into pathological processes in multiple sclerosis (MS). Nevertheless, to date only few studies have performed sodium MRI in MS. OBJECTIVES: We analysed total sodium concentration (TSC) in hyperacute, acute and chronic lesions in MS with (23)Na MRI. METHODS: (23)Na MRI and (1)H MRI were performed in 65 MS patients and 10 healthy controls (HC). Mean TSC was quantified in all MS lesions with a diameter of >5 mm and in the normal appearing white and grey matter (NAWM, NAGM)...
July 2016: Multiple Sclerosis: Clinical and Laboratory Research
Renny Mathew, Baltzar Stevensson, Mattias Edén
We characterize the intermixing of network-modifying Na(+)/Ca(2+) ions around the silicate (QSi(n)) and phosphate (QP(n)) tetrahedra in a series of 16 Na2O–CaO–SiO2–P2O5 glasses, whose P content and silicate network connectivity were varied independently. The set includes both bioactive and bioinactive compositions and also encompasses two soda-lime-silicate members devoid of P, as well as two CaO–SiO2 glasses and one Na2O–SiO2–P2O5 glass. The various Si/P↔Na/Ca contacts were probed by molecular dynamics (MD) simulations together with heteronuclear magic-angle-spinning (MAS) nuclear magnetic resonance (NMR) experimentation utilizing (23)Na{(31)P} and (23)Na{(29)Si} REDOR, as well as (31)P{ (23)Na} and (29)Si{(23)Na} REAPDOR...
April 30, 2015: Journal of Physical Chemistry. B
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